Conventionally, an apparatus has been suggested (Patent Document 1) in which, when an operation element is stereoscopically displayed on a screen and an operator touches a touch panel, an operation instruction to the operation element stereoscopically displayed by a stereoscopic display apparatus is detected based on coordinate data indicating the touched position, a parallax image of the operation element formed by a stereoscopic merging part is changed, and the shape of the operation element stereoscopically displayed on the stereoscopic display apparatus is changed. For example, when the operation element is represented by an image of a push-button-type switch, if the image of the switch is touched on the touch panel for ON/OFF, display of the image of the switch is changed to stereoscopic display or flat display according to ON/OFF, thereby improving operability.
Also, an operation panel apparatus has been suggested (Patent Document 2) in which a stereoscopic parallax image is displayed on a display part and is switched to a flat image before an operation is performed on a touch panel, thereby improving operability.
On the other hand, a visual line direction detecting apparatus has been suggested (Patent Document 3) in which visual lines of both eyes of a driver are detected, a comparison is made between the detection results and a standard visual line movement pattern in a normal driving state according to the state of a road where a vehicle has traveled during a detection period, it is determined which of the visual lines of both eyes is similar to the visual line movement pattern, and then an eye with a visual line direction more similar to the visual line movement pattern is determined as a dominant eye.